The long-term objective of this proposal is to determine, using enzymological studies, the genetic lesion for muscular dystrophy in the chicken. Fertile eggs from line 307, 412 and 413 supplied by the University of California at Davis, will be hatched in local hatchery and the chicks used in these studies. Rates of synthesis and degradation of AMP aminohydrolase and pyruvate kinase will be examined in vivo and in muscle cells in culture. The results of this study and measurement of the rate of clearance of AMP aminohydrolase and pyruvate kinase should provide the information necessary to determine if the lowered activities of these enzymes in dystrophic muscle result from enhanced degradation or leakage into extracellular space. The structure and synthesis of carbohydrate components of AMP aminohydrolase will also be investigated. Finally, a preliminary study of lysosomes from normal and dystrophic chicken breast, and mixed leg and thigh muscle will be initiated.